Detergent compositions



Patented Nov. 7, 1944- U ME to STATES PATENT oFFie DETERGENTCOMPOSITIONS No Drawing. Application September 22, 1941, Serial No.411,884

7 Claims.

This invention relates to certain new compositions of matter havingbleaching and detergent properties. More particularly, it relates to drystable mixtures containing an alkaline inorganic peroxygen compound, theanhydride of an organic acid, and a compound possessing detergentproperties. This application is, in part, a continuation of ourcopending application Serial No. 332,728 filed May 1, 1940, now Patent2,287,- 064, issued June 23, 1942.

Our invention relates more especially to the new and improvedcompositions, suitable for use as detergents, prepared by compounding asolid peroxygen compound such as sodium perborate monohydrate, a solidorganic acid anhydride such as succinic anhydride, phthalic anhydride,benzoic anhydride, maleic anhydride, or glutaric anhydride, and a dry,water-soluble detergent such as soap, trisodium phosphate, or varioussynthetic detergent agents. relates to stable dry compositions obtainedby compounding an alkaline detergent, a solid inorganic peroxygencompound, and an organic acid anhydride, which compositions, when addedto water, will yield detergent preparations having bleaching andoxidizing properties. These solutions are characterized by the presenceof either an organic monoperacid or its salt.

In the past, bleaching and oxidizing compositions of high activitycomprising peracids or persalts, suitable for utilization under variousconditions of alkalinity or acidity, could be produced only by chemicalreaction directly at the point of use. Stable dry compositions suitablefor addition of water or aqueous liquids to form bleaching and oxidizingcompositions of activity greater than that of the inorganic peroxides,or suitable when containing an alkaline detergent for use as a combinedbleaching and cleaning agent of high activity, were notavailable to theindustry. Previous attempts to prepare for commercial use drycompositions which are stable on storage and which would possess usefuldetergent properties when dissolved in water have generally aimed atproducing mixtures which,upon dissolution in water, yielded oxidizingsolutions having the characteristics and bleaching activity of hydrogenperoxide. Our principal aim is the preparation of dry compositions,stable on storage, which compositions when added to water or aqueousliquids will form detergent compositions containing, notperoxides ortheir salts, but organic monoperacids or their salts. The organicperacids and persalts possess increased bleaching activity and exerttheir oxidizing efiects at lower temperatures and with greater rapiditythan the peroxides or inorganic percompounds.

The organic monoperacids are a class of organic acids which are producedwhen the hy-- droxyl group containing the ionizable hydrogen Moregenerally, our invention atom of an organic acid is replaced by theperhydroxyl group, --OOH. Thus, monopersuccinic acid having the formulaCHLCOOOII mcoon may be regarded as derived from succinic acid, havingthe formula cmcoon H2.COOH

by replacement of one of the hydroxyl groups containing an ionizablehydrogen atom by the perhydroxyl group -OOH.

Our previous work with the peracids, and especially with themonoperacids, has impressed us with the fact that these acids and theirsalts are definitely superior to inorganic peroxide compounds such ashydrogen peroxide when employed for oxidizing or bleaching purposes.Their bleaching and oxidizing activity is greater than that of inorganicperoxides such as hydrogen peroxide, and it is exerted with greaterrapidity and at lower temperatures. The peracids and persalts,especially the monoperacids and monopersalts, also function over a widerrange of acidity and alkalinity, and therefore may be regarded as moresuited for universal application under the various conditionsencountered in commercial bleaching operations.

Since solutions of the peracids and persalts are not stable when storedfor any considerable period of time, it has been necessary in the pastto prepare the solution by chemical reaction wherever needed. Methodsavailable for their preparation have required careful control ofreactants, careful maintenance of reaction conditions, the use ofrelatively high concentrations of the reacting chemical compounds, andof fairly long reaction periods. As a result the art has made little orno industrial use of these oxidizing compounds.

In our copending patent application Serial No. 317,318, filed February5, 1940, now U. S. P. 2,284,- 477, we have described a method for thepreparation of the peracids and persalts which is more of storage, andwhen employing the method of our copending application it is generallynecessary to prepare the solution of the peracid or the persalt at theplace-where its use is intended. a

By providing a dry, stable mixture containing,

in addition to one or more alkaline detergents, an inorganic peroxygencompound and an organic acid'anhydride or its equivalent, we haveprovided a method permitting preparation of the peracids as neededwithout the necessity for exercising control of the proportions of thereagents, or careful control of the reaction at' the time and I place atwhich it is desired to utilize the composior persalts are to be utilizedfor industrial purposes.

Our improved compositions, while capable of producing the peracid orpersalt as" needed by simply adding the mixture to water at the place ofuse, nevertheless possess satisfactory stability for commercial storageand shipment. It is evident that our improved stable, dry mixtures ofdetergent, peroxygen compound and acid anhydride may be viewed, for allpurposes, as a stable peracid composition, thus rendering it possible toutilize the peracids and the persalts in commercial deterging operationsconveniently and without the necessity for careful control orproportioning at the point of use.

Accordingly, one of the objects of this invention is the preparation ofa stable dry composition which composition, when dissolved in water orin aqueous solutions, will yield an effective detergent solutionexerting the superior oxidizing and bleaching properties characteristicof the organic peracids and their salts. Another. object of thisinvention maybe said to be the preparation of a ,dry stable detergentcomposition which may be stored for indefiniteperiods without danger ofchemical instability but which will, nevertheless, when dissolved inwater yield solutions of the monoperacids or their salts, chemicalcompounds which in aqueous solution exhibit marked and efiectivebleaching activity. In brief, the primary object of our invention is thepreparation of a stable dry composition which can be stored indefinitelybut which is instantly available, simply by dissolving the solid mixturein water or aqueous liquids, to yield solutions of superior detergentproperties. The attainment of these objects involves developments of theutmost importance in the art of preparing detergent preparationsexerting bleaching and oxidizing properties, for never before has itbeen possible to prepare a dry stable composition capable of yielding aperacid or persalt when dissolved in water which would be stable for anindefinite period. Nor has it been previously possible to preparedetergent preparations containing stable solutions of peracids orpersalts, as needed, without the necessity for careful proportioning ofthe reagents andcontrolof the reaction used to produce the peracids or,persalts at the point where their use is intended.

In thev past organic acids such as succinic acid have sometimes beenincorporated in admixture with solid percompounds such as sodiumperborate. The purpose of these acids, however, has been solely that ofreducing the alkalinity of the solution resulting when the preparationis dissolved .in water. The acid employed for this purpose is one whichreacts with alkali to form a solutionof reduced alkalinity. Ascontrasted with this, the compounds that we use, the organic acidanhydrides or their equivalents, e. g. succinicanhydride, phthalicanhydride, glutaric anhydride, etc., instead of reacting with the alkalito result in a solution of lowered alkalinity, react with thepercompound when dissolved in water to form a peracid or persalt of theperacid. Acids corresponding to the anhydrides mentioned, for examplesuccinic acid, phthalic acid, and glutaric acid, do not react in aqueoussolution with percompounds such as sodium perborate to form theperacids. They merely react with any alkali present to reduce thealkalinity of the detergent preparation resulting. Accordingly, weutilize in admixture with the solid inorganic peroxygen compound such assodium perborate, the organic acid anhydrides or their equivalents.Although the latter will ordinarily hydrolyze in aqueous solution, theyreact preferentially with the peroxygen compound under these conditions,to form the desired monoperacid or its salt. The ability to react inaqueous solution in this way is characteristic of the organic acidanhydrides and equivalent substances.

In preparing our stable dry compositions of matter containing a compoundpossessing detergent properties, an alkaline inorganicperoxygencompound, and an organic acid anhydride or its equivalent, whichcompositions do not contain suflicient water or moisture to permitchemical reaction between the components of the mixture before the solidproduct is dissolved in an aqueous liquid, we may utilize a variety ofindividual compounds. We prefer, however, to utilize as the inorganicalkaline peroxygen compound sodium perborate monohydrate, NaBO3.H2O. Asorganic acid anhydride we may utilize a large variety of suchanhydrides, but generally, because of their ready availability and somwhat lower cost, we prefer to use such organic acid anhydrides assuccinic anhydride, phthalic anhydride,

adipic anhydride, benzoic anhydride, and glutaric anhydride. Generallythe non-toxic organic acid anhydrides are desirable for use in ourcompositions, but in some cases. of course, anhydrides of toxicity of agreater or less degree, e. g. maleic anhydride may be utilized. Whilesodium perborate monohydrate is a preferred solid inorganic peroxygencompound, by reason of its availability and low cost, we may utilizeother solid peroxygen compounds such as other perborates; alkali,alkaline earth and other peroxides;

percarbonates, persulfates, perphosphates, par-- ticularly the sodiumand other alkali metal salts, etc. These peroxygen compounds may beeither anhydrous or in the hydrated state as long as they do not containsufiicient free or uncombined waterto interfere with the obtainment'of adry mixture. Among suitable peroxygen compounds are urea peroxide, zincperoxide, magnesium peroxide, calcium peroxide and perphosphates such asthose having. the compositions NEMPzOmZI-IzOz the ratio of the molecularweights or these two compounds. When admixed with a water-solubledetergent, these compositions, when dissolved in water or aqueousliquids, will react to give greater yields of the peracid or its saltper unit weight of dry solid composition.

However, it is possible to control the acidity and alkalinity of theaqueous solution of the peracid to persalt by controlling the ratio ofthe amount of inorganic peroxygen compound present in the mixture to theamount of acid anhydride. In many cases, or course, it may be moredesirable to obtain this control of the pH of the aqueous solution byother means, in which case ordinarily equimolar amounts of the peroxygencompound and acid anhydride would be utilized. Compositions containingother than equimolar proportions of the two components are neverthelessalso useful. A composition containing a stoichiometric excess of onecomponent over the other may be particularly suitable for someindustrial or commercial purposes. For example, we have preparedmixtures containing from 40 mole percent to 83 mole percent of sodiumperborate monohydrate and have utilized these compositions containing,in addition, an alkaline detergent, to prepare the peracid or its saltin aqueous solution, which solution is particularly useful by reason ofits oxidizing and detergent properties.

In addition to the inorganic peroxygen compound and organic acidanhydride, there is present in the dry composition a compound possessingdetergent properties. Ordinarily we prefer to utilize dry, water-solubledetergents such as MP-189 and NIP-200, water soluble detergents of theso-called Reed Process type, which form the subject matter-of U. S. P.2,197,800. However, it is not essential to use synthetic detergents, aswe have found that any detergent may be utilized, provided it does notadversely affect the stability of the compound, and is eithersubstantially free from water, or contains moisture in such conditionthat the water is not available for reacting with the organic acidanhydride in the mixture. Among such suitable watersoluble detergents wemay specify dehydrated solid soaps; anhydrous salts possessing detergentproperties; alkyl and aryl sulfonates and their derivatives, as well asmixtures or combinations thereof; fatty alcohol sulfates and phosphates;organic phosphonic' acid derivatives; naphthenic acid derivatives; andsimilar substances possessing detergent properties. We have, forexample, secured very satisfactory detergent preparations when suchsubstances as anhydrous sodium carbonate, tetrasodium pyrophosphate,trisodium phosphate, anhydrous soaps, or similar watersoluble agentshave been included.

The preparation of detergent solutions having increased oxidizing andbleaching activity is readily carried out simply by adding the drystable composition to the desired quantity of water. The solution'isagitated for a suitable time, usually only a few minutes are necessary,in order to insure complete solution of the material.

The loss of oxidizing and bleaching properties during storage of thecomposition is negligible, since our dry stable detergent preparations,as long as they remain out of contact with water, are stable forindefinite periods. Such compositions can be commercially stored orshipped, without danger of decomposition, in ordinary packages, as theydo not require special containers or shipping means. The properproportioning of the material in preparing solutions of peracids andpersalts is automatically maintained when the initial dry composition isprepared, thus rendering unnecessary any special proportioning orcareful control at the point of use when preparing the detergentsolutions.

It is apparent that we have provided means for utilizing the rapidandpowerful bleaching and oxidizing properties of the organic peracidsand their salts in detergent preparations for industrial purposeswithout the necessity for special control-or careful reaction at thepoint where the products are to be employed for commercial purposes. Nospecial adjustments are necessary when the stable dry composition isdissolved in water, and the resulting detergent preparation is capableof immediate utilization.

As examples of our dry stable detergent preparations containing acompound possessing detergent properties, an inorganic peroxygencompound, and an organic acid anhydride, the following may be given.These examples demonstrate the stable character of our improved compositions during storage, as well as their effective detergent action.The concentration of an aqueous oxygen-yielding composition or solutionis frequently given in terms of its volume concentration. The volumeconcentration of such a solution isthe number of cubic centimeters ofoxygen gas, measured at 0 C.-and 760 mm. of mercury pressure, which isreleased upon complete decomposition by one cubic centimeter ofthe,,solution at 20 C. Commercial solutions of hydrogen peroxide, suchas those sold under the trade-mark name Albone, are generally of volumeconcentration, or yield, upon complete decomposition, 100 cc. of oxygengas per 00. of solution. This corresponds to an H202 content of 27.6% byweight.

Example 1 In order to demonstrate the superior stability during storageof our dry stable compositions, mixtures of sodium perborate monohydrateand succinic anhydride were stored for various periods at 32 c.

The loss in active oxygen was determined for each preparation at variousintervals during storage. The table below gives the composition of themixture and the average loss of active oxygen per month over aseven-months storage period.

A dry stable detergent preparation was prepared by mixing 25% of sodiumperborate mono hydrate, 25% of succinic anhydride, and 50% of thehereinabove identified synthetic detergent NIP-189. -All percentages are-by weight based on the totalweight of the solid detergent preparation;v

Cotton fabric was washed in' a solution containing approximately onepound of the dry stable detergent per 100 pounds of fabric treated. Forpurposes of comparison, other trials were made using various otherdetergents in connection with the same cotton fabric, the amounts ofthese detergents being substantially one pound per 100 pounds of fabrictreated. At the end' of each treatment the average percent increase inwhiteness per Washing was obtained, the fabric being washed in each casetwenty times in the alkaline detergent solution. The results are givenin the following table.

Average per cent increase in Detergent composition whiteness per washingobtained in 20 washings Sodium perboratc+succinic anhydride-l-MP-lSQ. 0.5Q 5089 i 0. 1| MP-l89. L 0. l5 Soap-l-sodium perboratc 0. 5OMP-l89+sodium perborate 0.27 Sodium perborate+suceinic anhydndc+soap 0.48

Example 3 Samples of cotton muslin were stained with strawberry,raspberry, peach, tomato juice, black tea, green tea, cocoa containingmilk, cofiee containing cream, beer, and wine stains. The cotton muslinwas then washed with the various detergent preparations given in Example2. The various Washing agents, as well 'as'the percent stain removal,(average for all stains), are given in the following table. This tableshows the percent stain removal after the first washing, after fivewashes, and after ten washes.

. Per cent stain removal alter-- Detergent composition I wash 5 washes lwashes Sodium perborate succinic anhydride+MPl89 78. 6 Soap 54. 8 57. 858. MP-189 48. 3 58. 6 58. 5 Soap-i-sodium perborate. 59. 6 65.9 74. 6MP-189+sodium perborate. 45. 1 80. 3 81. 9 Sodium perborate succinicanhydride+soap 51.0 73. 5 73. l

' Complete.

The results plainly show the superiority of our new detergent,comprising a dry stable mixture of sodium perborate monohydrate,succinic anhydride, and synthetic detergent MP-189 (socalled Reedprocess type product).

In preparing our improved compositions we prefer to use succinicanhydride, as well as other solid non-hygroscopic anhydrides, such asphthalic anhydride, maleic anhydride, and glutaric anhydride. However,condensation products of anhydrides with certain other organiccompounds, such as the product formed by reaction between maleicanhydride and cyclopentaiene, may be used in place of the organic acidanhydride in preparing our improved detergent compositions.

There may be present in our composition. in addition to the organic acidanhydride, peroxygen compound, and solid detergent, an agent forcontrolling the pH of the solution resulting when the composition isdissolved in water or other aqueou liquid. Among. such agents are alkalisalts such as anhydrous soda ash, trisodium phosphate, and tetrasodiumTpyrophosphate. Dry solidmaterials which are acidic in reaction, such ascitric acid, preferably dehydrated citric acid, as well as tartaricacid, may also be included in our composition for controlling thealkalinity or acidity of the resulting solution.

Our improved detergent compositions are valuable in commercial laundryand bleaching operations. They are a also valuable as householdlaundering compounds, scouring mixtures for various purposes, combinedbleaches and shampoos, deodorizing agents, for cleaning and bleachingleather, as a flux for cleaning metals, and as preparations to beutilized in place of soap.

It should be understood that various changes may be made in theproportions, ingredients, and amounts which have been given asillustrative of preferred embodiments of our invention without departingfrom the scope thereof. Thus, various additional ingredients may beincorporated in the dry stable composition, or the proportions of theingredients may be varied from those hereinbefore given as illustrative.The scope of the invention is therefore not to be restricted merely topreferred embodiments thereof, but isto be interpreted'in accordancewith the prior ,art and appended claims.

We claim: j

1; A dry stable detergent composition which yields in aqueous solutionan oxidizing agent of high activity, said composition comprising a solidinorganic peroxygen'compound, an organic acid anhydride, anda soliddetergent.

2. A dry stable detergent composition, suitable for yielding a solutionexhibiting oxidizing properties when dissolved in water, whichcomposition comprises a solid inorganic peroxygen compound, an organicacid anhydride, and a solid detergent, said composition containing lessthan sufficient available moisture to permit chemical reaction betweenthe constituents threof upon standing during storage.

3. A dry stable detergent composition which when dissolved in wateryields an oxidizing solution of high activity, said compositioncomprising sodium perborate monohydrate, an organic acid anhydride, anda solid detergent.

4. A dry stabledetergent composition comprising sodium perborate.monohydrate, succinic anhydride, and a solid water-soluble detergent.

5. A dry stable detergent composition comprising sodium perb'oratemonohydrate, phthalic anhydride, anda solid water-soluble detergent.

6. A dry stable detergent composition comprising sodium perboratemonohydrate, glutaric anhydride, and a solid water-soluble detergent.

'7. A dry stable detergent composition comprising a solid inorganicperoxygen compound, an organic acid anhydride, a solid water-solubledetergent, and a bufier.

. JOSEPH S. REICHERT.

.SAMUEL A. MCNEIGHT.

ARTHUR A. ELSTON.

